<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        width: 0;
        height: 0;
        margin: 50px auto;
        border-bottom: 130px solid #f00;
        border-left: 50px solid transparent;
        border-right: 50px solid transparent;
      }

      .box::before {
        content: "";
        width: 0;
        height: 0;
        position: absolute;
        border-bottom: 150px solid #f00;
        border-left: 200px solid transparent;
        border-right: 200px solid transparent;
        transform: translate(-200px, 113px) rotate(38deg);
      }

      .box::after {
        content: "";
        width: 0;
        height: 0;
        position: absolute;
        border-bottom: 150px solid #f00;
        border-left: 200px solid transparent;
        border-right: 200px solid transparent;
        transform: translate(-206px, 113px) rotate(-36deg);
      }
    </style>
  </head>
  <body>
    <div class="box"></div>
  </body>
</html>
